RNAketen

RNAketen is a synthetic RNA-like polymer that incorporates a keten-based linkage into the backbone. Introduced in speculative and experimental discussions as a concept for reactive RNA analogs, RNAketen exists mainly in research settings and has not been observed in nature. The design aims to preserve information-carrying capacity while enabling programmable backbone reactivity for post-synthetic modification.

RNAketen strands retain canonical bases and base pairing, but one or more phosphate diesters are replaced by a keten-containing bridge. The keten linkage offers an activated motif that can participate in post-synthetic ligations, cycloadditions, or addition reactions under defined conditions. Nucleoside units are assembled by standard solid-phase synthesis using modified phosphoramidites; protective groups are chosen to tolerate the keten functionality.

Properties and synthesis: In vitro studies show that RNAketen can form base pairs in short sequences, while backbone reactivity can be triggered by light or chemical stimuli to cause crosslinking, cleavage, or ligation. Stability depends on sequence, solvent, and substituents on the keten bridge. Behaviour in living cells remains largely untested, and cytotoxicity is not established.

Applications and research status: Potential uses include reversible crosslinking for RNA–protein interaction studies, programmable nanostructures, and responsive biosensors. Early work explores dynamic networks and origami-like assemblies that respond to stimuli. RNAketen remains a niche topic in nucleic acid chemistry, with challenges in scalable synthesis and cellular compatibility.

History and nomenclature: The name RNAketen combines RNA concepts with keten-inspired reactive chemistry, reflecting its backbone-focused functionality. It is discussed primarily in theoretical and experimental contexts as a probe of reactive backbones rather than a practically deployed biomolecule.